Such a valve generally comprises a body defining an inlet duct and an outlet duct for a fluid and receiving a valve member that is movable between a closed position in which it closes the outlet duct and an open position in which it is spaced apart therefrom by means of an actuator member fastened to a support element secured to the body. By way of example, the actuator member is an electromagnetic actuator member associated with a spring for returning the valve member into its closed position.
When the valve member is in the closed position, the pressure acting on the valve member beside the inlet duct differs from the pressure acting on the valve member beside the outlet duct. The force that results from this pressure difference tends to hold the valve member in its closed position by adding to the return force exerted by the spring. To bring the valve member into its open position, the electromagnetic actuator member therefore needs to provide sufficient force to overcome the combined action of the spring and of the pressure difference. This requires an electromagnetic member that is dimensioned accordingly, thereby presenting relatively large size and relatively high levels of electricity consumption. In addition, the force that needs to be delivered is not constant and depends on the pressure difference that exists between the two faces of the valve member.
To mitigate that drawback, it is known to use flexible sleeves of elastomer material, each having one end closed by the valve member and an opposite end connected to the support element in such a manner as to form a chamber. The chamber communicates with the outlet duct via an opening formed through the valve member so that the same pressure exists both in the chamber and in the outlet duct. The valve member is returned to the closed position by a spring interposed in the sleeve between the valve member and the support element. As a result the valve has a relatively large number of parts, thereby lengthening the duration and the complexity of assembly. In addition, assembling the sleeve and the spring is quite difficult. Furthermore, given the shape of the sleeve and the deformation to which it is subjected, the sleeve is made of an elastomer, which presents only limited ability to withstand fuel, unless it is prohibitively expensive. The flexibility of the sleeve also makes it necessary to provide means for guiding the valve member.